Miley, who just got engaged to Liam on May 31 and is sporting a 3.5-carat antique diamond ring on her left hand, splashed in the water with her bearded pal, who is allegedly her assistant Cheyne Thomas.

Sporting a sexy white bikini and flaunting her numerous tattoos, Miley sipped a drink while she chatted with Cheyne, hopefully about her hunky husband-to-be Liam. But insiders tell OK! they're not sure Miley and Liam will ever make it down the aisle.

"They love each other, but they're relationship is a total roller coaster," a source close to the couple tells OK!. "None of their friends are expecting them to actually make it down the aisle."